Objective:To review a case of congestive heart failure (CHF) due to a thyroid-stimulating hormone (TSH)secreting pituitary adenoma (TSH-oma) concomitant with Takotsubo cardiomyopathy in an elderly patient.Methods: We describe the clinical course, laboratory data, imaging studies, and management of the patient and provide a brief literature review regarding Takotsubo cardiomyopathy associated with hyperthyroidism.Results: A 76-year-old woman was admitted to our hospital for CHF treatment. Chest X-ray and electrocardiogram (ECG) showed cardiomegaly and broad T-wave inversion, respectively. Furthermore, left ventricular angiogram and subsequent coronary angiogram showed mild hypokinesis of the apex, without signs of obstructive coronary disease. Pulmonary hypertension was determined through right-heart catheterization. Accordingly, we clinically diagnosed this patient with Takotsubo cardiomyopathy complicated with pulmonary hypertension. Administration of β-blockers and angiotensin-receptor blockers markedly improved the abnormal ECG findings and wall motion due to Takotsubo cardiomyopathy. However, the cardiomegaly and pulmonary hypertension remained. We then detected hyperthyroidism with inappropriate TSH secretion. Brain magnetic resonance imaging revealed a pituitary macroadenoma, suggesting hyperthyroidism due to TSH-oma. Octreotide administration immediately led to the normalization of thyroid hormone secretion, which in turn improved the hyperthyroidism, cardiac enlargement, and pulmonary hypertension. Transsphenoidal surgery was safely performed. Pathologic investigation confirmed the diagnosis of TSH-oma.Conclusion: We report a rare case of Takotsubo cardiomyopathy complicated with hyperthyroidism due to TSH-oma in an elderly patient. Clinically, CHF is an important sign of hyperthyroidism in the elderly. Octreotide administration could be useful for the peri-operative management of elderly patients with TSH-omas and cardiovascular complications. (AACE Clinical Case Rep. 2018;4:e115-e123) Abbreviations: CHF = congestive heart failure; ECG = electrocardiogram; LAR = long-acting release; SITSH = syndrome of inappropriate thyroid-stimulating hormone secretion; TRH = thyrotropin-releasing hormone; TSH = thyroidstimulating hormone; TSH-oma = thyroid-stimulating hormone-secreting pituitary adenoma; TR-PG = tricuspid regurgitation pressure gradient e116 Heart Failure Due to TSH-oma, AACE Clinical Case Rep. 2018;4(No. 2)